Log Bird Feeder - 23 DIY Birdfeeders That Will Fill Your Garden With Birds (my note: I haven't looked at all of these, but at least one is a terrible idea. The window birdfeeder -- birds could fly into the glass and hurt themselves.
you could add some fish to your water reclamation tank for a small aquaponics system. Grow a few plants to feed the fish and this forms a closed system. There is no need to fertilize, the fish do it for you! Permaculture at its finest!